Percussion devices, as used in particular for producing horizontal ground boring devices, are generally driven by means of an impact piston which is moved back and forth within the housing and which, in the process, depending on the desired movement direction of the device, strikes a front or a rear impact surface. The kinetic energy of the impact piston transmitted thereby ensures acceleration of the percussion boring device within the ground.
In general, a reversal of the movement direction is achieved in that the central position (between the two reversal points) of the impact piston is shifted from a front position to a rear position or vice versa. Thus, depending on position, the impact piston strikes either the front or the rear impact surface and thereby defines the movement direction of the device.
From the prior art, various designs are known, by means of which the central position of the impact piston can be shifted, and thus the movement direction of the device can be changed.
For controlling the movement direction, a guide tube which is fixed on the housing and a control sleeve which can be axially shifted on the guide tube are used, wherein the impact piston can be axially shifted on the control sleeve. In particular, if the impact piston can be axially shifted on a control sleeve and the control sleeve has a great length, the impact piston can act on the control sleeve during the movement, warping the control sleeve, for example, as a result of which the service life of the control sleeve can be reduced, which causes increased repair and/or maintenance costs. Furthermore, in this case, due to increased friction, the performance of the percussion boring device can be strongly reduced. Moreover, it is possible that the housing of the percussion boring device is bent by lateral forces in the ground. In that case, the angular offset between control sleeve and impact piston can occur, as a result of which the impact piston and thus the entire percussion boring device can reach a standstill.